code: def _len_guards(M):
      """Handle small or incorrect window lengths"""
      if int(M) != M or M < 0:
          raise ValueError(
              "Window length M must be a non-negative integer"
          )
      return M <= 1
  
imports: import warnings
  import cupy
  import numpy
label_desc: Use image node_id 1 for calling a global function with example usage: _len_guards(M) and returns: unknown